Question 55)
Which of the following are methods of the Thread class?
1) yield()
2) sleep(long msec)
3) go()
4) stop()
Answer to Question 55)
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Question 56)
Which of the following methods are members of the Vector class and allow you to input a new element
1) addElement
2) insert
3) append
4) addItem
Answer to Question 56)
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Question 57)
Which of the following statements are true?
1) Adding more classes via import statements will cause a performance overhead, only import classes you actually use.
2) Under no circumstances can a class be defined with the private modifier
3) A inner class may under some circumstances be defined with the protected modifier
4) An interface cannot be instantiated
Answer 57)
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Question 58)
Which of the following are correct event handling methods
1) mousePressed(MouseEvent e){}
2) MousePressed(MouseClick e){}
3) functionKey(KeyPress k){}
4) componentAdded(ContainerEvent e){}
Answer 58)
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Question 59)
Which of the following are methods of the Collection interface?
1) iterator
2) isEmpty
3) toArray
4) setText
Answer 59)
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Question 60)
Which of the following best describes the use of the synhronized keyword?
1) Allows two process to run in paralell but to communicate with each other
2) Ensures only one thread at a time may access a method or object
3) Ensures that two or more processes will start and end at the same time
4) Ensures that two or more Threads will start and end at the same time
Answer 60)
Answers
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Answer 1)
Objective 1.2)
1) The code will compile and run, printing out the words “My Func”
A class that contains an abstract method must be declared abstract itself, but may contain non abstract methods.
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Answer 2)
Objective 4.1)
4) The code will compile but will complain at run time that main is not correctly defined
In this example the parameter is a string not a string array as needed for the correct main method
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Answer 3)
Objective 4.3)
1) public
2) private
4) transient
The keyword transient is easy to forget as is not frequently used. Although a method may be considered to be friendly like in C++ it is not a Java keyword.
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Answer 4)
Objective 1.2)
2) The compiler will complain that the Base class is not declared as abstract.
If a class contains abstract methods it must itself be declared as abstract
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Answer 5)
Objective 1.2)
1) To get to access hardware that Java does not know about
3) To write optimised code for performance in a language such as C/C++
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Answer 6)
Objective 1.2)
4) Success in compilation and output of “amethod” at run time.
A final method cannot be ovverriden in a sub class, but apart from that it does not cause any other restrictions.
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Answer 7)
Objective 1.2)
4) Compilation and execution without error
It would cause a run time error if you had a call to amethod though.
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Answer 
Objective 1.2)
1)Compile time error: Base cannot be private
A top leve (non nested) class cannot be private.
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Answer 9)
Objective 1.2)
4) P1 compiles cleanly but P2 has an error at compile time
The package statement in P1.java is the equivalent of placing the file in a different directory to the file P2.java and thus when the compiler tries to compile P2 an error occurs indicating that superclass P1 cannot be found.
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Answer 10)
Objective 1.1)
2) An error at run time
This code will compile, but at run-time you will get an ArrayIndexOutOfBounds exception. This becuase counting in Java starts from 0 and so the 5th element of this array would be i[4].
Remember that arrays will always be initialized to default values wherever they are created.
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Answer 11)
Objective 1.1)
2)myarray.length;
The String class has a length() method to return the number of characters. I have sometimes become confused between the two.
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Answer 12)
Objective 8.2)
3) A Frame with one large button marked Four in the Centre
The default layout manager for a Frame is the BorderLayout manager. This Layout manager defaults to placing components in the centre if no constraint is passed with the call to the add method.
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Answer 13)
Objective 8.2)
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